<!DOCTYPE html>
<html lang="zh-CN">
<head>
    <meta charset="UTF-8">
    <title>spring-boot-单例Demo</title>
    <style>
        .box {
            width: 200px;
            height: 200px;
            background-color: skyblue;
        }
    </style>
</head>
<body>

    <div class="box"></div>

</body>
</html>